1. Field of the Invention
This invention relates to a method of reclaiming styrene and other products from polystyrene based materials. In particular, the invention relates to use of solvents approved by governmental agencies to be of low toxicity in a pre-treatment container used to receive the materials to be depolymerized.
2. Description of Related Art
U.S. Pat. No. 5,502,263 (the '263 patent) describes a process for recycling polystyrene trash using a manufactured liquid, "styrene oil" (defined in the '263 patent), as a solvent for the polystyrene during the processing. A preferred embodiment of that recycling process involves placing a dissolving tank, equipped with a removable lid and partially filled with styrene oil, in each industrial or commercial site which routinely discards polystyrene, especially foamed polystyrene. An employee of each site would place its discards into the local dissolving tank as they are discarded, thus eliminating the need for voluminous storage space for discards between trash collections, and also substantially reducing the cost of trash collection. Moreover, the use of styrene oil as an aid in collecting the discards is doubly useful, as it is not only a strong solvent for polystyrene, but also greatly assists in the later processing of the polystyrene into styrene monomer.
Although styrene oil is believed to have a very low toxicity, its toxicity has not yet been officially established by the Environmental Protection Agency or OSHA. Should a significant delay occur in obtaining approval for the use of styrene oil in dissolving tanks, which are frequently opened within occupied facilities, the use of this particularly efficient method of trash collection may be precluded for some time. Therefore, there exists a need for a pre-processing method using a solvent that already has been governmentally approved for use within occupied facilities.